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By F. N. Kissell

The applicability of the "direct method" for determining the methane content of virgin coalbeds was tested. Preliminary results indicate that the direct method, when applied to exploration cores, can be successfully used to estimate coalbed gas content and also approximately predict the total gas emission from a prospective mine located in the coalbed at the exploration site.

Jan 1, 1973

By T. C. Campbell

This Bureau of Mines publication presents an analysis of information related to the transportation of bituminous coal by unit trains and slurry pipelines. Even for short hauls from mines to markets, transport costs frequently account for between one-third and one-half of the delivered price of coal. Minimizing these costs has become an even more critical objective for hauls from the western mines than for hauls from farther east. Factors related to minimizing costs and transporting the western coal receive special attention. Although no general rule of preference is likely to be developed that can be applied to all shipments, both rail and pipeline service will be needed on an increasing scale. The study should provide useful background information and analysis for government and industry in approaching investment decisions in the mining and transportation industries.

Jan 1, 1975

By P. M. Gruzensky

Several experiments have been carried out in efforts to evaluate qualitatively a variety of electrolytes for refining bismuth. Most extensive work was done with the basic tartrate, hydrochloric acid, and hydrofluosilicic acid electrolytes. Deposits that are smooth and adherent can be obtained from these three electrolytes if low cathode current densities are employed. All three electrolytes were effective in purifying crude bismuth considerably, with additional purification indicated in each instance by a reelectrolysis step. With the basic tartrate electrolyte best results were obtained when the electrolyte was at 40° C, and contained at least 100 grams of bismuth per liter, An apparent disadvantage was depletion of bismuth from this electrolyte, causing the deposits to become spongy and nonadherent.

Jan 1, 1956

By John J. Henn

As part of the U.S. Department of the Interior programs on rutile, authorized by the Office of Emergency Preparedness in June 1967 under provisions of the Defense Production Act, the Bureau of Mines reviewed available literature on major proposed processes for producing rutile substitutes. The processes are grouped according to the major processing step, and important operating features are described. Sixty-one references are cited.

Jan 1, 1970

By Blade O. C.

This report is one of a series made by the Bureau of Mines under a cooperative agreement with the Coordinating Fuel and Equipment Research Committee of the Coordinating Research Council, Inc., on the characteristics of commercial aviation gasolines. The series of surveys is a continuation of like work conducted from 1940 to 1946 by the National Bureau of Standards under a similar cooperative agreement. A list of reports of previous surveys is given at the end of this paper.

Jan 1, 1950

By James M. Stuckey

In a search for improved methods of upgrading tar obtained by low-temperature carbonization of coal, monoethanolamine (MEA) was found to be effective in extracting tar acids from coal tar distillates derived from a subbitunwous and a lignite coal. Patch extractions showed that both yield and purity of the extracted acids improved with increasing volume ratios of monoethanolamine to tar acid, varied from 1:4 to 8:1. Yield improved, but purity decreased as the concentration of monoethanolamine was changed from 30 to 70 volume-percent, and as the concentration of tar acid in distillate was increased ad from 14 to 45 percent. In a continuous countercurrent extraction employing a double solvent (monoethanolamine and hexane) approximately 80 percent of the tar acids was extracted from 170° to 350° C. tar distillate when using 1.6:1 volume ratios of amine:tar acids. Tar acids isolated from his extract, although of improved purity, contained appreciable quantities of neutral oils and some tar bases. Aqueous monoethanolamine was not effective for extracting the last 10 to 15 percent of tar acids in 170° to 350° C. distillate oil from lignite coal. The highest yield of isolated tar acids and the best recovery of monoethanolamine were obtained by diluting the extract with water and saturating with C02. Some losses of solvent were encountered when aqueous monoethanolamine solutions were heated through decomposition of the amine with the liberation of ammonia.

Jan 1, 1960

By E. F. Foerster

The Bureau of Mines used a diphenyl ether calorimeter to determine the heat contents of natural and synthetic blast-furnace slags. For solid slags, enthalpy (HT-H298) at 1,448° to 1,680° K ranged from 282.1 to 348.5 cal/g (±3 percent); liquid slag values were 400.1 to 514 cal/g (±3 percent) in the temperature range between 1,626° and 1,890° K. Experimental results for liquid slags were 14.3 to 16.2 percent higher than the enthalpies calculated from thermodynamic tables; values for solid slags ranged from 5.3 percent lower to 3.9 percent higher than calculated values. Experimental results for liquid synthetic slags ranged from 14.9 to 24.3 percent higher than the calculated enthalpies; values for solid synthetic slags were from 1.0 to 3.4 percent higher.

Jan 1, 1967

By J. R. Thoenen

During 1928 questionnaires covering the calendar year 1927 were sent to over 1700 quarries: producing stone for purposes other thaw cutting to dimension. These inclined producers of stone for limn burning; cement manufacture, rip rag, and crushed stone. The various rinds of stone represented were limestone, trap rock, sandstone, granite, and marble. Replies received from limestone producers prior to November, 1928, were compiled into tables and published in February, 1925, as a preliminary report (Bureau of Mines Report of Investigation 2911).

Jan 1, 1930

By Ralph V. Higgins

The present methods of appraising the long-range performance of oil reservoirs are based upon physical properties of the crude oil and the permeability of the reservoir rock. By means of these methods the performance of a reservoir may be estimated throughout its entire life. Before these methods were used, the future performance was estimated mostly by extrapolating pressure-decline curves -a method that is satisfactory for extrapolating only for a short period into the future. One factor that affects satisfactory long-range prediction of reservoir performance is the extent to which small changes in the physical properties of the oil and differences in the choices of relative permeability influence the calculated oil recovery. Selection of the physical properties of the samples to represent those of the oil and rock for the entire reservoir is difficult. This report is concerned with the error in calculated recoveries that may result from these inherent difficulties.

Jan 1, 1956

By T. W. Johnson

The United States Bureau of Mines, in cooperation with the Natural Gas Department of the American Gas Association, has been studying actively for the past-several years the flow of natural bas through high--pressure pipe lines.4 This report deals with that part of the study involving the design of pipe-line, systems consisting of lines laid parallel to each other. The lines are deferred to as the original line and the parallel line. The paralleling line may or may not extend the entire length of the original line; however, the parallel line is, connected at its two ends to the original line. As a result of the large expansion of the natural-gas industry almost all markets within economic distance from the developed gas fields have at least one pipe line supplying them with natural gas. Small increases in the consumers' demand for natural gas can be met usually by increasing operating pressures, but any marked increase in demand necessitates paralleling sections of the existing systems. It is believed that to a large extent future

Jan 1, 1934

By G. Asai

The purpose of this Bureau of Mines investigation was to determine the properties of arc-melted iron-chromium alloys ranging in chromium content from 12 to 50 wt.-pct. Alloys were prepared by consumable-electrode arc melting of electrodes composed of high-purity chromium and high-purity iron. Alloys were fabricated to rod and sheet, and the following data were obtained: Electrical resistivity, hardness, tensile strength, and impact strength at room temperature; and creep-rupture life at 650° C. (1,200° F.). As the chromium content of the annealed alloys varied from 12 to 50 pct., the properties varied as follows: The electrical resistivity increased proportionally from 41 to 53 microhm-cm,; the Rockwell hardness varied from A 38 to A 58; the tensile strength ranged from 52,000 to 96,000 p.s.i.; the impact strength of V-notched charpy specimens varied from 140 to 405 ft.-lb., and the 100-hour creep rupture life at 1,200° F. varied from 5,000 to 16,000 p.s.i.

Jan 1, 1962

By D. P. Schlick

As of June 30, 1970, Federal regulations required the operator of each underground coal mine to maintain the average concentration of respirable dust below legislative standards. As of March 1, 1971, over 152,000 respirable dust samples have been processed by the Bureau of Mines. Approximately 75 percent of underground working sections are being sampled in accordance with Federal regulations. Results indicate that 72 percent of the sections which have completed at least one basic sampling cycle are below 3.0 mg/m3, the standard in effect under the Federal Coal Mine Health and Safety Act of 1969 (P.L. 91-173). Notices of Violation were issued on 1,670 underground mines for failure to begin a sampling program; Withdrawal Orders were issued in 64 of these instances. Notices of Violation were issued on 1,121 sections where applicable dust levels were exceeded; Withdrawal Orders were issued in seven of these instances. There are 381 mining sections currently operating on permit; from the interim Compliance Panel.

Jan 1, 1971

By A. J. Kraemer

For a number of years the Bureau of Mines has conducted semi-annual survey to determine the changes in the characteristics of the rotor gasoline being sold in the United States. Certain cities have been decided upon as points of origin of samples. Tare choice of these cities has been governed by their situation as the representative of a more or less definitely bounded marketing territory. Samples have been taken on or about the fifteenth day of January and July of each year. In the collection of the samples an attempt has been made to get a representation of the important types of motor fuel being sold, and also to tame into consideration the proportion of tie total consumption that is supplied by the different marketers. It is therefore felt that the survey affords a reliable indication of the quality of the gasoline being sold throughout the United States at the time of sampling. The figures in Table I, below, were obtained by averaging the end points of the least volatile and most volatile samples of gasoline. For example, of 850 samples analyzed in 1919, the 10 per cent (85 samples) having the highest end points, and the 1C per cent having the lowest end points were averaged. These averages are represented in the table as the "Maximum 10 per cent" and the "Minimum 10 per cent", respectively. The same scheme was used in the succeeding surveys.

Jan 1, 1925

By William H. Lyon

In 1950 the Program Staff of the Department of the Interior undertook an exploratory study in the projection of energy requirements of the nation. This work was reported in Bureau of Mines Information Circular 7582 by H. J. Barnett. In that preliminary study Mr. Barnett, after exploring the nature of the energy economy in some detail, evolved a method for estimating how much energy will be required in the future, based on estimates of trends in efficiency of energy utilization in specific applications, the physical output of specific energy-consuming industries, size of the population, productivity advances in the economy at large, consumer preferences, and other factors. Considerable new information was developed regarding the nature of energy demands and the possible levels of requirements for each fuel under various assumed business conditions. The study analyzed the interrelationships, including substitutions, among the fuels and emphasized the need for viewing the energy economy as an integrated albeit complex whole. This exploratory study showed a need for a single comprehensive statistical re-port that would assemble and show in a uniform manner the diverse published statistical data on energy commodities now scattered through many publications. A particularly important need was for a set of historical statistics showing the production and consumption of all energy on a B.t.u. basis. As the prospective size and nature of the future energy requirements of the nation are matters of continuing importance, this report was prepared to assist further investigations of the subject. In this report the authors undertake to assemble and present in tabular form, on a uniform basis, the production and use of each of the fuels and electric energy in the United states for three census years -1929, 1939, and 1947. The year 1947, rather than a later year, was selected because it is the most recent year for which census data are available showing the consumption of fuel by each of the manufacturing industries. It is hoped that making data for these 3 years available in one re-port will provide the needed statistical background for further studies of fuel requirements and supplies.

Jan 1, 1951

By G. H. Gronhovd

This report describes the design and initial operation of a slagging gasification pilot plant installed by the Bureau of Mines at the Lignite Research Laboratory, Grand Forks, N. Dak., in 1958-59. The tests covered in this report were conducted over a period of about 2 years, beginning in April 1959. The pilot plant was designed for eventual operation at pressures ranging from 400 to 600 p.s.i.g. (pounds per square inch gage); however, for the preliminary test reported here, the gasifier was fitted with a low-pressure slagging section and operated at atmospheric pressure and at 80 p.s.i.g. The reason for using a low-pressure slagging section for initial operation was to facilitate modifications in design during the development of a reliable slagging procedure.

Jan 1, 1962

By E. J. Matson

The Bureau of Mines has been investigating deposits of critical and essential minerals in the United States since 1939. The Rush Creek lead-zinc deposit, Mono County, Calif. (fig. 1), was examined by W. T. Benson in July 1944 and again in September 1945 by D. W. Butner, engineers of the Bureau of Mines. From the results of these preliminary examinations, a core-drilling program (fig. 2) was started in August 1946 and continued until November 1946, when work was stopped on account of inclement weather. Field work was again started in May 1947 and completed in June 1947. The drilling program was laid out to develop the horizontal .and vertical extensions of showings exposed in surface pits.

Jan 1, 1949

By J. L. Hoffman, F. W. Wood, R. A. Beall, W. E. Anable

For melting and purifying reactive and refractory metals , two electronbeam furnaces have been constructed and operated on the principle of highpowered vacuum diodes . It was necessary to design the vacuum and electrical systems , mechanical features , and operating procedures to cope with dynamic conditions . Vacuums of 10-5 torr , tens of kilowatts of power at 5 to 10 kilovolts , and the evolution of impurities at thousands of liters per minute constitute a challenging combination . The furnaces have been used to melt either button specimens weighing several hundred grams or , by feeding material as a consumable electrode , small ingots weighing several kilograms . Hafnium is among the metals that can be purified . For example , hafnium starting material with Rhn 94B was softened to Rhn 70B after 2 hours of melting under a 25 - kw electron beam , and impurity levels were reduced as follows : Oxygen , from 700 to 350 ppm ; nitrogen , from 71 to 20 ppm ; hydrogen , from 6 to 1 ppm ; aluminum from 75 to < 20 ppm ; chromium , from 80 to < 10 ppm ; iron , from 100 to 40 ppm ; and silicon , from 40 to < 20 ppm .

Jan 1, 1963

By D. A. Rice

As part of its mission, the U.S. Bureau of Mines continues to develop technologies that will enable cost-effective compliance with environmental requirements. To this end, investigations to improve the kinetics of chalcopyrite dissolution by simultaneous grinding-leaching in ferric sulfate solution were conducted using the Bureau-designed turbo mill. The development of such a hydrometallurgical process would provide a nonpolluting alternative to conventional smelter technology. The effects of mill rotational speed and volume percent solids on the leaching time and energy required for copper extraction from chalcopyrite were evaluated. The results of this laboratory study have shown that the simultaneous grinding-leaching of chalcopyrite concentrate using the turbomill is technically feasible with essentially 100 pet extraction of copper being possible at 90° C. An optimal energy consumption of 1,153 kW?h/st of copper leached was found in batch testing with the mill operating at 400 rpm with a slurry containing 35 vol pet chalcopyrite. This energy consumption, while higher than other proposed leaching processes (about 600 kW?h/st), is of the same order of magnitude. Further refinement of the energy requirements would require additional testing using a continuous circuit. Leaching times of less than 1 h, for 80 pct copper extraction, are achievable using the turbomill grind-leach process.

Jan 1, 2010

By Charles Vaught

The U.S. Bureau of Mines evaluated the self-contained self-rescuer (SCSR) donning proficiency of 243 miners. These workers were from eight underground coal mines in the eastern United States. The objectives of the study were (1) to gather information on skill levels, since all miners in the study had prior instruction and opportunity to practice donning the apparatus, and (2) to summarize a quality control procedure useful in conducting periodic evaluations of donning proficiency. The sampling procedure used proved to be both reasonable and efficient in gathering information on training effectiveness. It also provided a good statistical base for making informed site-specific decisions regarding SCSR training needs. Results from the observed samples at each of the eight mines indicate a wide variability across sites. The rate at which miners failed to isolate their lungs varied from 3.3 to 40.0 pet. Concomitantly, proficiency rates (miners either performing adequately or demonstrating a perfect 3 + 3 sequence) ranged from 13.3 to 63.3 pet.

Jan 1, 2010

By Suresh K. Bhatt

This U.S. Bureau of Mines report reviews major developments in continuous haulage technology for underground coal mines. Haulage systems, both in use and under development, were investigated through a comprehensive literature search and visits to mines and manufacturers. The systems include flexible conveyor train, mobile conveyor, monorail bridge conveyor, multiple-unit continuous haulage, extensible, and belt turning systems. Strengths and weaknesses of the systems are assessed in light of their operating under remote control and their application to the computer-assisted continuous mining machine research being conducted by the Bureau. Through mining scenarios, candidate haulage systems are conceptualized to be consistent with the capabilities of the mining machine.

Jan 1, 1991